The long-lasting pop band Fleetwood Mac
is also one of the most controversial, its several changes of style and
personnel often arising from romantic entanglements rather than musical
differences. Bob Weston, who has died aged 64 of a gastrointestinal
haemorrhage and cirrhosis of the liver, was the band's lead guitarist in
the early 1970s, and contributed to both the evolution of its sound and
its turbulent history.

Born in Plymouth, Devon, he began lessons
on the violin at the age of 8, switching to the guitar at 12. Like many
others, he was swept up in the rhythm and blues boom of the early 1960s,
citing as influences in interviews such figures as Muddy Waters and Hubert Sumlin (accompanist of Howlin' Wolf), as well as the jazz musician Django Reinhardt.

By the mid-1960s, Weston was in London,
looking for groups to join and recording sessions to play on. His first
taste of success came with The Kinetic, a group of British musicians
who worked mainly in France. As well as making the album Live Your Life
(1967), they supported such luminaries as Jimi Hendrix and Chuck Berry
in Paris shows.

Back in London, Weston's skills as a creative
blues guitarist led to work with the singer Aliki Ashman and the
organist and singer Graham Bond. In 1970, Weston joined the backing
group of the blues singer Long John Baldry,
touring Europe and the US as well as playing on Baldry's album
Everything Stops for Tea (1972), produced by two of the singer's
proteges, Rod Stewart and Elton John.

Baldry's band sometimes
performed on the same bill as Fleetwood Mac, which since 1968 had been
in the forefront of British blues groups. This was due mainly to the
imagination and skill of the singer and guitarist Peter Green, who had
crafted such big hits as Albatross and Man of the World (both 1969).
However, Green's departure in 1970, followed by the loss of fellow
guitarists Jeremy Spencer and Danny Kirwan, had left the band
rudderless. In 1972, the remaining members decided to recruit Dave
Walker of the blues rock band Savoy Brown as lead vocalist, and Weston
as lead guitarist.

He recalled meeting Kirwan in The Speakeasy, a
musicians' club in London's West End. "He rather sarcastically wished me
the best of luck, adding 'You're going to need it.'"

Bob Weston in 1973, the year of Fleetwood Mac's Penguin album, on
which he co-wrote songs. Photograph: Fin Costello/Redferns/Getty Images

Kirwan's remark proved to be prophetic, although to begin with,
Weston made a significant contribution to the group's sound on stage and
in the studio. Fleetwood Mac was in transition from being a blues band
to a more melodic pop-rock one, and Weston was adept at both styles. He
played on the 1973 albums, Penguin and Mystery to Me, co-writing several
songs. Penguin is regarded by many Fleetwood Mac aficionados as one of
the group's most underrated recordings.

They were also on a
schedule of relentless touring, which was beginning to take its toll.
Walker was unceremoniously fired early in 1973, there were tensions
between the husband-and- wife team of Christine Perfect and John McVie,
and when Weston began an affair with Jenny Boyd, the wife of drummer
Mick Fleetwood, the scene was set for a split. This duly came in
Lincoln, Nebraska, during an American tour in October 1973.

Weston
was woken by a phone call summoning him to the tour manager's hotel
room. He was told that other group members had already departed, that
the remaining tour dates would be cancelled and that his services were
no longer required. He was put on the next flight back to London.

This proved to be a cathartic moment for Fleetwood Mac.
Within a year they had re-formed with the lineup that would go on to
create Rumours (1977), although in the interim their manager had formed
another "Fleetwood Mac" to fulfil US tour commitments. It has sometimes
been alleged, inaccurately, that Weston was part of that group.

In
fact, he landed on his feet in London, where his Fleetwood Mac
credentials opened doors. He had abortive discussions with George
Harrison about collaborations, but toured with blues veteran Alexis
Korner and played on Sandy Denny's final album, Rendezvous (1977). His
most lucrative project was with the actor Murray Head, star of Hair and
Jesus Christ Superstar. Weston featured on Head's album Say It Ain't So
(1975), a big hit in France and Canada, and led Head's touring band.

Weston
also recorded three solo albums, Nightlight (1980), Studio Picks (1981)
and There's a Heaven (1999), and spent much of the last two decades
writing or arranging music for films and television in France and
Britain. Still in touch with older musicians, he had been due to record
with the ex-Rolling Stones guitarist Mick Taylor. He is survived by his
younger brother, Peter.

• Robert Joseph Weston, guitarist and songwriter, born 1 November 1947; died 3 January 2012